Monetizing the blog

No you cannot. WordPress.com has been running advertising on our free hosted blogs since 2006. Many bloggers do not know this because despite the fact they ticked the box required to get a free blog, they did not read the ToS. Many also do not read features page, or advertising entry in the support documents after registering their username and blog(s). Also note that as the ads do not display to us when we are logged in, and as many use browsers with ad blockers when logged out, they may not realize they are there at all. The only way to get rid of all advertising on our free hosted WordPress.com blogs is to purchase an annually renewable No-Ads upgrade.

In a nutshell no blogger initiated advertising, retailing or reselling the work created or services provided by anyone other than yourself is allowed on free hosted wordpress.COM blogs. E-commerce transactions via shopping carts and the like cannot be conducted on free blogs from and being free hosted by wordpress.COM

As a web designer, this is one of the things I dislike having come up, and it will at some point come up because a client has done a webinar or attended a seminar at the local Holiday Inn on getting rich off internet advertising.